How Our Diet Affects Our Mood

Photo by Andres Ayrton

Numerous studies have shown that the food we eat affects the chemical composition of our brain and alters our mood. Our diet affects our cognitive capabilities, including alertness and the production and release of neurotransmitters, the chemical messengers that carry information across nerve cells. Neurotransmitter activity is primarily affected by the nutrients found in foods and the interaction among those nutrients in foods. 

The delicate brain chemical balance is partially maintained by the blood-brain barrier. The brain is highly susceptible to changes in body chemistry resulting from nutrient intake and, more importantly, nutrient deficiency. The proven connection between nutrition, brain function and behavior can be observed through the brain’s capability of receiving, storing and integrating sensory information, while initiating and controlling motor responses. These functions correspond to mental activities and form the basis for our behaviors. 

Mounting evidence from epigenetic studies confirms that specific nutrients alter our brain development and susceptibility to diseases. While neural impulses mainly result from cell membrane sodium-potassium exchange, numerous other food ingredients, such as complex carbohydrates, amino acids (tyrosine and tryptophan), fatty acids, and particularly omega-3 fatty acids, affect the permeability of the cell membrane, neurotransmitter metabolism and glial cells. 

Ultimately, high-fat diets induce insulin resistance and obesity via production of interleukin-1β (IL-1β) in multipotent stem cells1, interleukin-6 (IL-6) in fat2, and tumor necrosis factor-alpha (TNF-α) in muscle, liver, and fat tissue3. IL-1β, IL-6, and TNF-α are all signaling cytokines produced by an activated immune system. Cytokines are secreted by certain immune cells and have an effect on other body cells. They essentially keep the inflammatory processes going4. These immune-mediated cytokines are likely to influence personality traits, especially if diet-induced inflammation has become habitual.

Elevations in IL-6, TNF-α, and/or c-reactive protein (CRP, synthesized by the liver in response to general, non-specific  inflammation), are more commonly found in hostile-prone individuals5, 6, 7, 8 ,9, 10. This means that if one easily becomes upset or angered, there might be a biological basis rooted in inflammation.

It is possible that sample characteristics of a population, such as age, sex, and socioeconomic status, influence the association between hostility and the inflammation we see11, 12, 13. For example, individuals with hostile or aggressive behavior have enhanced cardiovascular reactivity to stress14, 15.  This enhanced reactivity to stressful situations can contribute to higher concentrations of pro-inflammatory cytokines16. 

These studies suggest that more frequent and spiked increases in pro-inflammatory cytokines may accelerate a wide range of age-related illnesses. Put another way, hostile relationships impact our human physiology, through stress and inflammation, and set the stage for disease later in life.

Overall, three causal pathways are consistently demonstrated: 

1. Inflammation impacts one’s emotional state

2. One’s emotional state impacts inflammation

3. Bi-directional relationship between inflammation and emotional state 

Anti-inflammatory diets, in combination with lessened reactivity to stress and supportive social interactions, likely reduce aggressive behaviors, depressive-like syndrome, and general anxiety.

Specific combinations of whole foods used in a regular diet regime, like the Mediterranean diet, has shown a positive impact on maintaining brain function and lowering incidence of neurodegenerative diseases.  A Mediterranean diet, because of its anti-inflammatory nature, reduces IL-1β, IL-6, and TNF-α16, 17, and is a therapeutic approach to decrease “sickness behaviors” like hostility/rage and/or depression-like symptoms. The Mediterranean diet’s key components include increased consumption of vegetables, fruit, omega-3-rich fish, nuts, legumes, and olive oil. 

The optimal meals to reduce the risks of neurodegenerative diseases and enhance one’s mood are those that combine complex carbohydrates with lean proteins and colorful produce. Complex carbohydrates from whole foods, such as sweet potatoes, rolled oats, beans and quinoa, can increase availability of the chemical serotonin - which makes one feel good. Plant-based protein consumption, such as from beans and legumes, has been associated with higher levels of dopamine and norepinephrine, which are brain chemicals that enhance our mood, motivation and concentration. Fruits and vegetables are high in vitamins, minerals and antioxidants that nourish our body and have also been proven to boost happiness.

AUTHOR

Dr. Payal Bhandari M.D. is one of U.S.'s top leading integrative functional medical physicians and the founder of SF Advanced Health. She combines the best in Eastern and Western Medicine to understand the root causes of diseases and provide patients with personalized treatment plans that quickly deliver effective results. Dr. Bhandari specializes in cell function to understand how the whole body works. Dr. Bhandari received her Bachelor of Arts degree in biology in 1997 and Doctor of Medicine degree in 2001 from West Virginia University. She the completed her Family Medicine residency in 2004 from the University of Massachusetts and joined a family medicine practice in 2005 which was eventually nationally recognized as San Francisco’s 1st patient-centered medical home. To learn more, go to www.sfadvancedhealth.com.